Know your goals, like ReductiMat said. I'm 47 and have been pretty hard on my body, so I focus on injury prevention and keeping old issues at bay. Back, hips, shoulders - focusing on the backside of shoulders, core, and a little bit or all-round strength, which include pushups and pullups. I had a physical therapist friend help me design workouts, and it's none of the "cool" stuff you see jacked people do in commercial gyms. If my workout is more than 30-40 minutes I get totally bored, I'd rather be outside, so I keep it modest.
I ended out going with interlocking floor mat, a sandbag and a couple bands. That said, I'm considering one of those fragile select-a-weight dumbbell sets so I can do overhead presses. I can do quite a lot with this minimal setup. **** Edit: oh screw that, after watching Comrade Kettlebell, I'm getting a couple of those! So good!
I used to lift pretty hard with a nice home gym when I was in my late 20's. Got pretty strong for a lean guy, though I did it wrong, and it contributed to a major shoulder injury. Was telemarking on an icy day on some lines around Spanky's Ladder. Lost grip and starting sliding into some steep rocks and had to self arrest, which I did successfully, but it yanked my should pretty good at a weird angle. Tore my rotator to bits, and my doc, a great sports medicine Dr, said my weight lifting made it way worse since my front-of-shoulder and chest were stronger than my back-shoulder. When the adrenaline hit it popped everything forward, combined with the hard torque from a weird angle and I had a 1-year recovery (shoulda had surgery).
Moral of the story, get balanced while you get strong. Bikers hunch forward, so upper back and back of shoulders are key. And don't neglect those hamstrings to balance out our over-developed quads.
Fast forward 20 years and I started doing swim workouts to enable my love of surfing when I go on winter vacation. I also have a desk job and ride bikes, and did a lot of trail building. Again, lack of body balance and I developed thoracic outlet syndrome, which started as finger numbness on rides and got pretty bad, and my lower back always went out. Had to stop trail building at this point. Got set up on a program of strengthening/shortening the back of my neck and back of shoulders. Doc also said to do as much backstroke as crawlstroke on swim workouts.
The focus on my back with band work, hip hinges, and back bridges have really helped my shoulder and back injuries. Plus my posture is great! I'm really quite stoked on my ability to stay healthy now even with a f'd up back.
40-45 was rough for me. I was one of those guys who could crash and and mostly be able to shrug it off and throw dirt with abandon. Then BOOM, 40 hit and I was always messed up. I had to learn the hard way, but my current program of core and balanced strength has me riding long descents without stopping and happily doing trail work again, though I need to stay smart about moving rocks.